When people exercise, either at home or in a fitness club, they usually have some goal in mind, such as getting fitter, staying fit, increasing strength, losing weight, etc. To get the most benefit from exercise it is important that people know exactly what goal they have been set and how they are performing, both on an immediate real-time basis and over time. This leaves the person who has exercised with a number of key questions: How well have I done? How much energy did I exert and how many calories did I burn? Did I perform well against my target or exercise program? What was my target? Did I do better this time, compared to last time or my historical data? Am I improving and progressing my fitness level? Exactly how fit am I?
The current method of establishing a person's absolute maximum performance on any given piece of exercise equipment is to get that person to exercise to exhaustion while measuring the parameters of interest: heart rate, oxygen consumption, weight lifted, etc. This data provides an individual's maximum performance at that point in time i.e. the individual's 100% output or ability. However this may be only 60% of the standard for that individual's age or sex. Such standards (high, average, poor, etc) are available for aerobic fitness (VO2max) as established on a treadmill, bicycle, or step test and some physical performance tests.
This method, for most people, is impractical, since as you are improving in fitness, you would be required to retake the tests to track any change in fitness level.
Some current computer-based solutions for fitness training are essentially electronic versions of a performance card on which measured repetition and set data (for weight stack exercise machines) is stored and possibly compared to a target value. The feedback provided is minimal, and only provides information relating to targets for sets and repetitions, not in terms of overall health targets.